William Inglis and Son managing director Mark Webster has signalled his intention to step down from his role at the thoroughbred auction house.

Webster has told the board he will relinquish the position at the end of 2018 after 11 years with William Inglis.

He said he intends to cease being a full-time executive and will undertake more non-executive board roles and consulting work.

"Inglis is extremely fortunate to have had Mark at the helm for so many vital years in the company's history," chairman John Coates said in a statement.

"Under his leadership, the company has grown, met many challenges and is extremely well placed into the future.

"Mark's principal legacy is his key role in the sale of Newmarket, the purchase of the land adjoining the Warwick Farm racetrack, now known as Riverside, and the timely development of the multi-use Riverside Stables, auction auditorium and adjoining William Inglis Hotel - all world's best."

Webster will continue at Inglis as a non-executive director of the company.